The study will make a new examination of the pharmacotherapeutic agents which dentists routinely apply to dentin and to exposed dental pulp in the treatment of tooth pain, dental caries and in other operative dental procedures. The agents are used both to treat pulp inflammation and to protect and maintain the vitality of the tooth. Two attributes of commonly used pulp therapeutic agents will be examined. The release of the active principles of the therapeutic agents from the proprietary forms and the diffusion through dentin will be measured using radioactive tracers. The order of concentration which each drug reaches in the pulp and the duration for which this concentration is maintained will then be calculated. These data will be applied to the second part of the study. Since local blood flow is intimately linked with tissue vitality and the response of tissue to threat or insult, the effects of the agents on blood will be determined. In vitro biological models of blood vessel function will be used to examine the vasoactive effects of the agents. Homogenates of the proprietary forms of the agents will be screened for their effects on the model systems, and the threshold of action and optimal concentrations of the active principles determined. Correlations between agents and correlations with known clinical effects of the agents will be made. The agents to be studied play an important role in general dental practice, and the success or failure of the procedures in which they are used may have a profound effect upon the health of the individual. Data from this study, which will utilize new lines of investigation of the agents, will improve the rational use of those agents now available and will lead to the development of new approaches to vital pulp therapy.